Multifocals
Specific type of PD measurement that is taken for segmented multifocals
Binocular PDs
Formula used to calculate segment drop
seg height - B/2
Specific type of PD measurement that is taken for PALs
Binocular
Where is the add power located on a progressive lens?
Located temporally
After checking the screws, where do you begin standard bench alignment on a frame?
At the bridge
What is the add power of a bifocal lens that reads -3.00 in the distance and -0.50 in the segment?
+2.50
Formula used to calculate segment inset
(DPD - NPD)/2
The name of the point under the fitting cross
Prism reference point
Where to read/verify the add power of the lens
Near reference point
When the frame is twisted about the bridge
X-ing
Calculate horizontal decentration using FPD: 68mm PPD: 70mm
1 out each eye
Formula used to calculate horizontal decentration
(A+DBL - DPD)/2
Which vertex power is used to verify the distance prescription?
Back vertex power
Tolerance for progressive add power under 4.00D
+/- 0.12D
This material is commonly used in drill mounts but can stretch over time
Polycarbonate
Another name for a Franklin-style bifocal
Executive
Formula used to calculate Total Inset
(A+DBL - Near PD)/2
The process of purposefully inducing equal amounts of base down prism into progressive lenses during the surfacing process
Prism thinning
Formula used for horizontal decentration
(A + DBL)/2 - Mono PD
True or false? Drilling straight through poly all at once can result in an unstable mounting.
True
Blended bifocals are another form of _____
Round segment bifocal
R: -7.00 sph, L: -5.00 sph
Add: +1.50, Height: 18/16
Is this acceptable?
No, both lenses are greater than 3.375D and the heights are more than 1mm apart
Synonym for the MRP
PRP
Segment height is measured from ____ to _____
Where should the groove be placed on a high plus lens?
A uniform distance from the front surface of the lens